If there was some sort of voting/ranking method, then pictures could be submitted for a period of Jan 1 - Aug 31, and then the top 12 ranked pictures become the images. Alternatively, if the pictures should be somewhat appropriate (nio snow plowing pictures in July), then the voting could be categorized by month, and each month would have a winner.
The biggest problem would be the programming load put onto Ibrahim, there should probably be some safeguards such as each member can only rank each picture once.
Votong ends Aug 31, payment due by Sept 30, and calendars mailed by Nov 30.
Dave